Terminal structure for a multiconductor cable cooled by a circulating fluid

ABSTRACT

A terminal structure of a multiconductor electric cable wherein the terminal is in two parts and two groups of conductors of different polarities separated by a separating element are cooled by a fluid in a sealing sheath. According to the invention, an elastic sealing element is interposed between plane faces of the two terminal parts in the extension of the separating element. At least one rigid incompressible insulating element, thinner than the sealing element and interposed between said faces, limits the pressure exerted on the sealing element when clamping said parts together.

United States Patent Inventor Armand Carasso 71 Avenue du Roule, 92Neuilly-sur Seine, France 7 Appl. No. 854,839 Filed Sept. 3, 1969Patented Aug. 24, 1971 Priority Sept. 6, 1968 France 165,294

TERMINAL STRUCTURE FOR A MULTICONDUCTOR CABLE COOLED BY A CIRCULATINGFLUID 8 Claims, 3 Drawing Figs.

US. Cl 174/15, 174/19 Int. Cl H0lb 7/34 Field of Search 174/15 C, 16,19,20

[56] References Cited UNITED STATES PATENTS 2,702,311 2/1955 Botterillet al. 174/19 3,156,760 11/1964 Grove 174/15 3,363,047 l/l968 Grove174/15 Primary Examiner-Lewis H. Myers Assistant Examiner-A. T. GrimleyAttorney-Sughrue, Rothwell, Mion & Zinn I ABSTRACT: A terminal structureof a multiconductor electric cable wherein the terminal is in two partsand two groups of conductors of different polarities separated by aseparating element are cooled by a fluid in a sealing sheath. Accordingto the invention, an'elastic sealing element is interposed between planefaces of the two terminal parts in the extension of the separatingelement. At least one rigid incompressible insulating element, thinnerthan the sealing element and interposed between said faces, limits thepressure exerted on the sealing element when clamping said partstogether.

ATENTEU AUB24 l97i I W N K TERMINAL STRUCTURE FOR A MULTICONDUCTOR CABLECOOLED BY A CIRCULATING FLUID The present invention relates to electricmulticonductor kickless cables for conducting very high intensitycurrents and cooled by an axially flowing cooling fluid, such as, amongothers, the cables employed for connecting portable tongs to theresistance-welding stations or the supply cables of electric arcfurnaces, or the like.

It is known that these cables may carry, as the case may be, currentswhose intensity can be of the order of l0,000-50,000 a. per phase.

These cables must be very strong so as to be able to withstand thevarious mechanical stresses inherent in their use and in electromagneticphenomena. Further, their cooling by a circulation of a fluid agentcreates numerous problems, particularly as concerns the terminals, fromthe sealing point of view.

It is indeed known that these cables have a plurality of conductors eachof which consists of numerous threads of wire of small diameter twistedtogether in accordance with a special arrangement intended to reducefriction between the threads.

The problems created by the sealing are particularly difflcult to solvein respect of the terminals of multiconductor cables in which the twopolarities of the conductors are grouped under the same outer sheath,but separated from each other by a separating element, the conductors ofthe two polarities being either opposed or alternating. Indeed, theseterminals are made in two semicylindrical parts insulated from eachother but interconnected in a sealed manner.

Itis known that each of the two parts of the terminal comprises an innersemicylindrical axial passage communicating with the inner end face ofthe terminal and opening at its other end in a tapped aperture for theinlet of the cooling fluid, this axial passage serving to being thefluid on the axis of the cable and also being capable of serving as adeparture point of radial branch passages for the fluid which enablesthe periphery of the bundle of conductors to be irrigated.

As the two parts of the terminal must be electrically insulated fromeach other, there is usually placed therebetweenia plate of rigidinsulating material. However, this material does not afford asatisfactory seal.

Consequently, it is necessary to dispose a sealing element between eachhalf of the terminal and said insulating plate, around the axial passageand the cooling fluid inlet aperture.

These sealing elements are generally disposed in a recess provided forthis purpose in each part of the terminal, but this arrangement is onlyeffective if there is a precise positioning of the various clampingplanes, which precision is liable to be easily destroyed, in operation,under the action of the various electromechanical forces to which thecable is subjected.

The object of the invention is to provide a terminal structure having asealing device which is easy to make and efficient and reliable inservice.

The terminal structure according to the invention comprises two terminalparts having plane faces, an elastically yieldable insulating elementwhich is interposed between said faces and constitutes a sealing elementin the extension of an element separating the conductors of the phases,means clamping said terminal parts to form an assembly by, compressionof said elastically yieldable element, and at least one rigidincompressible insulating element having athickness less than thethickness of the elastically yieldable element in the free uncompressedstate and constituting an abutment limiting the pressure exerted on saidelastically yieldable element when clamping said two parts together.

According to one of the invention said sealing element has a pluralityof openings in each of which is disposed a rigid incompressibleinsulating element having a thickness less than that of said sealingelement in the free uncompressed state.

Further features and advantages of the invention will be apparent fromthe ensuing description with reference to the accompanying drawing.

In the drawing:

FIG. 1 is a perspective view, with a part cut away, of an end terminalfor a multiconductor cable having opposed polarities including a sealingelement according to the invention;

FIG. 2 is an exploded perspective view showing the arrangement of thevarious parts, and

FIG. 3 is a view of a modification of the sealing device disposedbetween the two halves of the terminal.

With reference to the drawing, the invention is shown applied to a cableA having a terminal 5 such as the type described in applicant's FrenchPat. No. 1,589,129.

This cable is of the type having opposed polarities comprising aplurality of conductors l and 2 of respectively positive and negativepolarity, in operation, the conductors of opposed polarities beingseparated by an insulating separating element 3 which axially extends inthe cable, the threads of each conductor being themselves maintained bya permeable textile sheath or the like in the known manner.

Each group of conductors 1, 2 is connected to a terminal 5 in the mannerdescribed in said French patent application.

7 The terminals 5 of each end of the cable are similar and consequentlyonly one thereof will be described.

The terminal 5 has two parts 6 of copper which have a generallysemicylindrical shape and are symmetrical relative to an end portion 7of the separating element 3 which is plane that is, has a rectangularcross section in this region and separates these parts and insulatesthem from each other.

Each half 6 of the terminal has at its outer end a flat portion 8, inthe known manner, adapted to be connected to the apparatus with whichthe cable is combined.

Each terminal half also has, on its inner plane face, an axial passage 9which extends from a radial tapped aperture 10 to its inner end, theradial aperture 10 being adapted to receive a cooling fluid supplynozzle in accordance with a known arrangement.

Longitudinal apertures 11 are also provided which open out on the innerend face of each terminal half 6, these longitudinal apertures beingadapted to receive the ends of conductors l, 2.

Further, at least one radial aperture 13 is provided in the vicinity ofthe end of each of the longitudinal apertures 12 and connects the end ofa groove 13, provided in the outer face of each half-terminal, with theaxial passage 9.

The end of each conductor 1, 2 is fitted in a plug 14 constituted by acopper sleeve and each plug 14 is then inserted in a longitudinalaperture 11 in which it is held by a press operation.

The two half-terminals 6 are maintained assembled by a screw 15 screwedin one of the half-terminals whose head and shank are insulated from theother half-terminal by an insulating sleeve 16, and by an outerinsulating sheath which is a force fit on the assembled terminal 5.Preferably this sheath 17 is held tight by a clamping collar of knowntype (not shown) and grooves 18 are provided on the outer face of theterminal 5 between the recess 13 and the aperture 10 so as to ensurethat the sheath 17 is well held in position.

The sheath 17 has an inside diameter equal to the diameter of theterminal 5 and greater than the outside diameter of the conductors l, 2surrounded by the tape 4 so as to leave a gap 19 between the sheath andthe conductors (FIG. 1) all around the latter.

Owing to this arrangement, the cooling fluid which enters the terminal 5by way of the apertures 10 flows along the axial passage 9 andthereafter flows axially in the center of the cable between theconductors l, 2 and by way of radial apertures 13, recesses 12' in theouter face of the terminal formed by the press operation for grippingthe plugs 14, and in the gap 19 between the conductors and the outersheath l7 and thus affords an extremely efficient cooling of all theconductors.

If desired, there can be provided between the conductors a spring orother flexible and permeable element affording axially a passage ofminimum section for the cooling fluid.

To ensure a complete seal between the two halves 6 of the terminal 5,the separating element 3, which can be for example of rubber, has arectangular-sectioned portion 7 which extends between the half-terminals6 and is clamped therebetween.

, However, the rectangular-sectioned portion 7 of the I separatingelement 3 must have a number of openings in the region of the apertures10 for the passage of the cooling fluid, in the region of the clampingscrew and at the end of the terminal in the region of an apertureprovided in the flat portion 8 and adapted to ensure the connection withthe electric apparatus in a continuous manner.

To preclude any flow or creep of the edges of the portion 7, there areprovided spacer members 21, 22 adapted to withstand the force clampingtogether the two halves of the terminal and limit the pressure exertedon the portion 7 of the separating element 3 which affords the seal. Forthis purpose, the thickness of these spacer members 21, 22 is a littleless than that of the portion 7.

These spacer members are advantageously of the material known under theTrademark Celoron (Trademark for macerated canvas or paper-basedindustrial laminated or molded plastics having high-impact strength) andare disposed in openings 23, 24 formed in the portion 7.

The spacer member 21 (FIG. 2) is constituted by a plate of Celoron"disposed in the opening 23 and having an aperture 31 in the region ofthe radial apertures 13.

lt sill be observed that there is a solid part 7' in the portion 7 ofthe separating element 3 between the openings 23 and 24 so that thelength of the longitudinal narrow marginal portions laterally definingthe openings 23 and 24 is restricted solely to these openings, whichthus reduces any tendency on the part of these sides to deform outwardlyof the terminal.

Owing to this arrangement, there is achieved a durable sealing of theterminal 5 by means of a simple device which is very easily assembled,while the two halves of the terminal are maintained at the same distanceapart throughout their length.

element adapted to be in the extension of said separating element andinterposed between and sealingly engaging said opposed plane faces andin a compressed condition radially of said half-terminals for sealingthe cooling fluid in said inlet apertures and said axial fluid passagefrom the exterior, screw means radially extending through saidhalf-terminals for assembling said half-terminals, and at least onerigid incompressible insulating element having a thickness less than theoverall thickness of said sealing elementin a free uncompressedcondition of, said sealing element, said incompressible element engagingsaid plane faces and constituting an abutment limiting the pressureexerted on said sealing element when radiallyv clamping said twohalf-tenninals against said sealing element and incompressible elementby said screw means.

2. A terminal structure adapted to receive a multiconductor electriccable of the type comprising two groups of conductors of differentpolarities separated by an insulating separating element and disposedwithin a sealing sheath and cooled by a fluid circulating within thesheath, said terminal structure comprising two half-terminals eachhaving a generally semicylindrical shape, an axial cooling fluid passagedefined by said half-terminals, aligned radial cooling fluid inletapertures in said half-terminals and communicating with said axial vcooling fluid passage, and aligned radial second apertures in Accordingto a modification of the sealing device for the terminal 5 shown in FIG.3, there can be provided a plate 25 of Celoron having a generallyrectangular shape and'including the necessary apertures l0, 15', 20'onto which is moulded a sealing element 26 of rubber which surrounds theaperture 10' by way of which the cooling fluid is supplied.

In this case, the parts of the Celoron plate onto which the sealingelement of rubber is moulded have a thickness which is locally reducedto permit the clamping of the sealing element in a manner limited by therest of the plate which thus performs its function of spacer member,said reduced-thickness parts serving solely as a support for the sealingelement 26.

In the embodiment of the sealing device shown in FIG. 2,

the elastically yieldable sealing element 7 is constituted by arectangular-sectioned portion of the separating element 3, that is, itis in one piece with the latter, This sealing element may of course be aseparate member, as in the embodiment shown in FIG. 3, and connected tothe phase-separating element 3 in any suitable manner, for example by anadhesive.

Although specific embodiments of the invention have been described, manymodifications and changes may be made defined in the appended claims.

Having now described my invention what I claim as new and desire tosecure by Letters Patent is;

l. A terminal structure adapted to receive a multiconductor electriccable of the type comprising two groups of conductors of differentpolarities separated by an insulating separating element and disposedwithin a sealing sheath and cooled by a fluid circulating within thesheath, said terminal structure comprising two half-terminals eachhaving a generally semicylindrical shape, an axial cooling fluid passagedefined by said half-terminals, aligned radial cooling fluid inletapertures in said half-terminals and communicating with said axialcooling fluid passage, and aligned radial second apertures in saidhalf-terminals for means fixing the terminal structure to aterminal-receiving part, opposed inner plane faces on said twohalf-terminals, an elastically yieldable insulating and sealing saidhalf-terminals for means fixing the terminal structure to aterminal-receiving part, opposed inner plane faces on said twohalf-terminals, an elastically yieldable insulating and sealing elementadapted to be in the extension of said separating element and interposedbetween and sealingly engaging said opposed plane faces and in acompressed condition radially of said half-terminals for sealing thecooling fluid in said inlet apertures and said axial fluid passage fromthe exterior, screw means radially extending through'said half-terminalsfor assembling said half-terminals, said sealing element comprisingopenings and spacer members of a hard insulating material disposed insaid openings, the thickness of said spacer members being less than thethickness of said sealing element in a free uncompressedcondition ofsaid sealing element, said spacer members engaging said plane faces andconstituting abutments limiting the compression of said sealing elementwhen radially clamping said half-terminals against said sealing elementand spacer members.

3. A terminal structure as claimed in claim 2, further comprising radialcooling fluid outlet apertures in said' half-terminals and communicatingwith said axial passage and with an outer groove in said half-terminals,one of said openings completely surrounding said outlet apertures inplanes containing said plane faces for the passage of the cooling fluidand another of said openings being in radial alignment with said secondapertures and said screw means to allow passage of said fixing means andscrew means, a further opening being provided in said sealing element inradial alignment with said inlet apertures.

4. A terminal structure as claimed in claim 1, wherein saidincompressible element comprises a plate which has an aperturecoincident with the fluid inlet apertures in the half-terminals andextends at least along the entire length of said axial cooling fluidpassage.

5. A terminal structure adapted to receive a multiconductor electriccable of the type comprising two groups of conductors of differentpolarities separated within a sealing sheath and cooled by a fluidcirculating within the sheath, said terminal structure comprising twohalf-terminals each having a generally semicylindrical shape, an axialcooling fluid passage defined by said half-terminals, aligned radialcooling fluid inlet apertures in said half-terminals and communicatingwith said axial cooling fluid passage, and aligned radial secondapertures in said half-terminals for means fixing the terminalstrucsaidopposed plane faces and in a compressed condition radially ofsaid half-terminals for sealing the cooling fluid in said inletapertures and said axial fluid passage from the exterior, screw meansradially extending through said half-terminals for assembling saidhalf-terminals, a rigid incompressible insulating element interposedbetween and engaging said plane faces and comprising an aperture inalignment with said cooling fluid inlet apertures, said sealing elementextending round said aperture in said incompressible element andextending on each side of said axial cooling, fluid passage and adaptedto extend into said sheath, and recessed portions in said incompressibleelement in which said sealing element is fixed by being moulded to saidrecessed portions, said recessed portions having a depth which is lessthan the thickness of said sealing element disposed in said recessedportions, when in a free uncompressed condition, whereby saidincompressible element constitutes an abutment limiting the pressureexerted on said sealing element when radially clamping saidhalf-terminals against said sealing element and incompressible ele mentby said screw means.

6. A terminal structure as claimed in claim 5, wherein said sealingelement forms one single piece with said element separating theconductors of opposed polarities.

7. A terminal structure as claimed in claim 1, wherein said sealingelement is separate from said separating element and secured thereto.

8. A terminal structure as claimed in claim 7, wherein said sealingelement is adhered to said separating element.

1. A terminal structure adapted to receive a multiconductor electric cable of the type comprising two groups of conductors of different polarities separated by an insulating separating element and disposed within a sealing sheath and cooled by a fluid circulating within the sheath, said terminal structure comprising two half-terminals each having a generally semicylindrical shape, an axial cooling fluid passage defined by said half-terminals, aligned radial cooling fluid inlet apertures in said half-terminals and communicating with said axial cooling fluid passage, and aligned radial second apertures in said halfterminals for means fixing the terminal structure to a terminalreceiving part, opposed inner plane faces on said two halfterminals, an elastically yieldable insulating and sealing element adapted to be in the extension of said separating element and interposed between and sealingly engaging said opposed plane faces and in a compressed condition radially of said halfterminals for sealing the cooling fluid in said inlet apertures and said axial fluid passage from the exterior, screw means radially extending through said half-terminals for assembling said half-terminals, and at least one rigid incompressible insulating element having a thickness less than the overall thickness of said sealing element in a free uncompressed condition of said sealing element, said incompressible element engaging said plane faces and constituting an abutment limiting the pressure exerted on said sealing element when radially clamping said two half-terminals against said sealing element and incompressible element by said screw means.
 2. A terminal structure adapted to receive a multiconductor electric cable of the type comprising two groups of conductors of different polarities separated by an insulating separating element and disposed within a sealing sheath and cooled by a fluid circulating within the sheath, said terminal structure comprising two half-terminals each having a generally semicylindrical shape, an axial cooling fluid passage defined by said half-terminals, aligned radial cooling fluid inlet apertures in said half-terminals and communicating with said axial cooling fluid passage, and aligned radial second apertures in said half-terminals for means fixing the terminal structure to a terminal-receiving part, opposed inner plane faces on said two half-terminals, an elastically yieldable insulating and sealing element adapted to be in the extension of said separating element and interposed between and sealingly engaging said opposed plane faces and in a compressed condition radially of said half-terminals for sealing the cooling fluid in said inlet apertures and said axial fluid passage from the exterior, screw means radially extending through said half-terminals for assembling said half-terminals, said sealing element comprising openings and spacer members of a hard insulating material disposed in said openings, the thickness of said spacer members being less than the thickness of said sealing element in a free uncompressed condition of said sealing element, said spacer members engaging said plane faces and constitutiNg abutments limiting the compression of said sealing element when radially clamping said half-terminals against said sealing element and spacer members.
 3. A terminal structure as claimed in claim 2, further comprising radial cooling fluid outlet apertures in said half-terminals and communicating with said axial passage and with an outer groove in said half-terminals, one of said openings completely surrounding said outlet apertures in planes containing said plane faces for the passage of the cooling fluid and another of said openings being in radial alignment with said second apertures and said screw means to allow passage of said fixing means and screw means, a further opening being provided in said sealing element in radial alignment with said inlet apertures.
 4. A terminal structure as claimed in claim 1, wherein said incompressible element comprises a plate which has an aperture coincident with the fluid inlet apertures in the half-terminals and extends at least along the entire length of said axial cooling fluid passage.
 5. A terminal structure adapted to receive a multiconductor electric cable of the type comprising two groups of conductors of different polarities separated within a sealing sheath and cooled by a fluid circulating within the sheath, said terminal structure comprising two half-terminals each having a generally semicylindrical shape, an axial cooling fluid passage defined by said half-terminals, aligned radial cooling fluid inlet apertures in said half-terminals and communicating with said axial cooling fluid passage, and aligned radial second apertures in said half-terminals for means fixing the terminal structure to a terminal-receiving part, opposed inner plane faces on said two half-terminals, an elastically yieldable insulating and sealing element adapted to be in the extension of said separating element and interposed between and sealingly engaging said opposed plane faces and in a compressed condition radially of said half-terminals for sealing the cooling fluid in said inlet apertures and said axial fluid passage from the exterior, screw means radially extending through said half-terminals for assembling said half-terminals, a rigid incompressible insulating element interposed between and engaging said plane faces and comprising an aperture in alignment with said cooling fluid inlet apertures, said sealing element extending round said aperture in said incompressible element and extending on each side of said axial cooling, fluid passage and adapted to extend into said sheath, and recessed portions in said incompressible element in which said sealing element is fixed by being moulded to said recessed portions, said recessed portions having a depth which is less than the thickness of said sealing element disposed in said recessed portions, when in a free uncompressed condition, whereby said incompressible element constitutes an abutment limiting the pressure exerted on said sealing element when radially clamping said half-terminals against said sealing element and incompressible element by said screw means.
 6. A terminal structure as claimed in claim 5, wherein said sealing element forms one single piece with said element separating the conductors of opposed polarities.
 7. A terminal structure as claimed in claim 1, wherein said sealing element is separate from said separating element and secured thereto.
 8. A terminal structure as claimed in claim 7, wherein said sealing element is adhered to said separating element. 